Bit-stock.



No. 878,404. PATBNTED FEB. 4, 1908.

I. LARSON.

BIT STOCK.

APPLICATION FILED JAN. 26. 1907.

2 SHEETSSHEBT 1.

I aniline/noes n/"Ma BTW 1 No. 878,404. PATENTED FEB. 4, 1908. I. LARSON.

BIT STOCK.

APPLICATION FILED JAN. 26. 1907.

2 SHEETS-SHEET z.

anuewtoz nu: mmms psrsns ca., WASHINGTON, n cy ISRAEL LARSON, OF SANDY, UTAH.

BIT-srocK.

Specification of Letters Patent.

Patented Feb. 4, 1908.

Application filed January 26. 1907. Serial No. 354.301-

To all whom it may concern:

Be it known that I, ISRAEL LARSON, a citi zen of the United States, residing at Sandy, in the county of Salt Lake and State ofUtah, have invented new and useful Improvements in Bit-Stocks, of which the following is a specification.

This invention relates particularly, to ratchet, braces used for boring, and for driving screws. The bit holder is adapted to be adjusted in four different positions, wit-h reference to the brace, so that it may be used in limited spaces, and the device is readily detached from the brace and connected with a straight handle, such as is used in ordinary screw-drivers. Ordinary braces are readily adapted for attachment to this improvement, gy forming a thread on the end of the sweep- The accompanying drawing illustrates the invention, its various parts being referred to by letters, similar letters denoting corresponding parts in the several views.

Figure 1 is a side view of the device, on a brace, and fitted with a boring bit. Fig. 2 is a view with the bit holder turned at a right angle to the brace; the latter being in cross section. Fig. 3 is a plan of the pressure plate. Fig. 4 is a section of the device with the bit holder in position. Fig. 5 shows a straight handle with its lower end in section. Fig. 6 is a side view of the bit holding jaws, partly in section. Fig. 7 is a plan of the lower end of the mortised plug. Fig. 8 is a front view of the bit holding jaws. Fig. 9 is a side elevation of a spring pawl. Fig. 10 is an end view of the outer threaded sleeve, and Fig. 11 is a plan of the bottom of the pawl controlling band.

The letter A designates the sweep bar, or crank of a brace, having the end bars a and a On a is secured the usual pressure knob B. The end of bar a is threaded to engage a plug C, partly threaded within and without and having the cross mortises c, c, at its lower end. These mortises are engageable by a rib or tenon d on the upper end of a threaded thimble D.

d is a tie-bolt having a threaded connection with the thimble D, and the bit stock F.

The parts C, D and the threaded end of the brace are covered by an outer sleeve E whose lower part is threaded to engage the thimble D and whose upper part is movable around the lug C, its upward movement being limitec by a jam nut e, which has a threaded connection with the plug C. A shoulder c on the inner periphery of the sleeve E engages an annular projection c on the plug (1, by which the sleeve is held in position.

The bit stock F is connected with the bit holder by a shaft 9 on the bit holder, and which passes through the lower part of said stock, and is held in place by a pressure plate secured thereto by a screw J. This shaft revolves loosely in the stock and has fixed thereon a ratchet wheel G which is engageable by spring pawls H, H, pivoted in said stock. These pawls are provided with sockets h in each of which is seated the end of an expansion spring 7L1, which normally keeps the pawls in engagement with the ratchet G. Either one of these pawls is disconnected from the ratchet by turning a band I so that its lower extension 71 will force in the upper end of the pawl. The inner face of the ends of this extension t have the bevel cut 2' by which the band easily moves over the pawl.

The outer end of the shaft 9 which forms a part of the bit holder, is enlarged into a slotted, outwardly threaded piece K, within whose slot is loosely seated the bit holding jaws M. At one end these jaws are loosely attached by a pivot fixed in one jaw, and extending through a hole p in the opposite jaw. The outer end of this hole p is enlarged at its outer end into a socket, which holds the enlarged end p of the said rivet. These jaws are further provided with the usual recesses to engage the edges of the bit shank, and also with longitudinal recess m on the outer side of each jaw. An expansion spring wire at occupies said recesses m and passes through holes 0 from one jaw to the other, normally holding the jaws open. A sleeve L covers the jaws M, and is screwed upon the piece K, its contracted openingl closing the jaws M upon the blank of the bit Q, as the sleeve is screwed on. If the 0 erating space is very limited, a plain hand e R having its lower end 1' threaded internally, may be screwed upon the thimble D to work the ratchet.

What I claim and desire to secure is 1. In a bit-stock, the combination with the end of a sweep bar, of a plug having cross mortises in its lower end, a threaded thimble, tenons on said thimble to engage said mortises, a threaded stock, a threaded tie-bolt engaging said thimble and said stock,

means to releasably hold said plug and said thimble in operative contact and means to connect said stock with a bit holder, as

specified.

2. The combination with the threaded end of a sweep bar of a plug having an exterior shoulder and with cross mortises in its lower end, a thimble partly threaded within and without, tenons on the upper end of said thimble to engage the, mortises in said plug, an internally threaded stock, a threaded tiebolt to engage said thimble and said stock, a sleeve having screw connection with said thimble; a shoulder on said sleeve abutting said shoulder on said plug, a jam nut on the upper end of said plug to hold said sleeve in position, a shaft rigid on a bit holder rotatable in said stock and a connection between said stock and said shaft, as described.

In testimony whereof I affix my signature, in presence of two subscribing witnesses.

ISRAEL LARSON.

Witnesses:

THOMAS J. ALMYR, WILLIAM E. JUDD. 

